Cron builder
Write a cron schedule and instantly see what it means and when it next runs. Nothing is uploaded.
Files are processed in your browser and never uploaded.
How to use Cron builder
Add your text
Type or paste your text into the input box. Everything is handled by your own browser, so nothing is sent to a server.
Read the result
The output updates as you type, so there is nothing to submit and nothing to wait for.
Copy or save it
Copy cron, Don puts the result on your clipboard.
What this tool does
Plain-English description
The expression is translated into a sentence as you type, so you can check that what you wrote is what you meant.
Next five run times
The next five run times are listed with dates, which catches the mistakes a description on its own will not.
Handy presets
Presets cover every minute, every 5 or 15 minutes, hourly, daily at midnight or 9am, weekdays, Sundays, the 1st of the month and every 6 hours.
Standard 5-field cron with ranges, lists, steps
Standard five-field cron is supported in full, including ranges, lists and step values, so what you build here works in crontab.
Works offline, no sign-up
Everything is parsed in your browser, so the schedule is never uploaded and the page works with no connection.
Frequently asked questions
Is anything uploaded?
No. The expression is described and the next run times are worked out entirely in your browser, with nothing uploaded. It works offline once loaded.
Which cron format does it use?
Standard 5-field cron: minute, hour, day of month, month and day of week, supporting stars, ranges like 1-5, lists like 1,15 and steps like every-five written as the slash form.
How are the next run times calculated?
It scans forward minute by minute from now and lists the next five matching times in your local timezone, exactly as a scheduler would fire them.
How are day-of-month and day-of-week combined?
Following the usual cron rule, if both are set the job runs when either matches; if only one is set, only that one applies.
Why might it say no upcoming runs?
Some expressions can never match, such as February 30th. If nothing matches within the next few years, that is reported instead of a run list.
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